Impaired glucocorticoid synthesis in premature infants developing chronic lung disease

Influence of antenatal steroids on the effect of early inhaled postnatal corticosteroids: a post-hoc analysis of the NEuroSIS trial

BACKGROUND

Few data are available on the interplay of antenatal and early inhaled postnatal corticosteroids. The NEuroSIS trial randomized extremely preterm infants to receive either early inhaled budesonide or placebo and analyzed the effect of study medication on bronchopulmonary dysplasia or death, as well as the effect on neurodevelopmental outcome at 18-22 months corrected age. Application of antenatal steroids may have had an influence on these outcomes.

OBJECTIVE

To analyze if antenatal corticosteroids (ANS) influenced the short- (BPD and death before 36 weeks PMA) and long-term (disability at 18-22 months corrected age or death before time of assessment) effects of early inhaled postnatal budesonide in NEuroSIS study participants.

METHODS

Post-hoc analysis of the intention-to-treat population of the NEuroSIS study. Generalized logits models were used to (1) predict risk of BPD, death before 36 weeks PMA and survival without BPD with application of ANS, NEuroSIS study treatment and gestational age as independent variables and (2) predict the risk of disability at 18-22 months corrected age, death before time of neurodevelopmental assessment and survival without disability, with ANS and gestational age as independent variables.

RESULTS

Application of ANS, added as an independent variable, did not change the effect of study medication on developing BPD (OR 0.79, 95% CI 0.67-0.93) and there was no association with the risk of death (OR 1.03, 95% CI 0.84-1.27) at 36 weeks PMA. ANS added as an independent variable showed an association with a reduced risk of death before time of completion of neurodevelopmental assessment (OR 0.60, 95% CI 0.44-0.81) and was associated with a reduced risk of disability at 18-22 months corrected age(OR 0.63, 95% CI 0.49-0.81).

CONCLUSION

ANS did not alter the reduction of BPD risk by study medication and there was no association with increased mortality in NEuroSIS study participants.

Prophylactic low-dose hydrocortisone in neonates born extremely preterm: current knowledge and future challenges

Prophylactic administration of low-dose hydrocortisone, at replacement dosage, targets inability of extremely low gestational age neonates (ELGANs) to respond to postnatal stress due to adrenal glands immaturity and is intended to prevent serious complications such as death and bronchopulmonary dysplasia (BPD). Increasing evidence from systematic reviews shows that prophylactic hydrocortisone reduces pre-discharge mortality, improves survival without BPD, favors patent ductus arteriosus (PDA) closure, and may have beneficial effects on cardiovascular stability and urine output. In contrast, an increased risk of spontaneous intestinal perforation when prophylactic hydrocortisone is combined with indomethacin and late-onset sepsis, particularly in infants of 24-25 weeks of gestation, have been reported as major adverse events. No significant negative impact on long-term neurodevelopmental outcomes following prophylactic hydrocortisone exposure was observed. Recent real-world data, despite their intrinsic methodological limitations, generally confirm the benefits observed in clinical trials, even with additional potential benefits and without increased adverse events. Ongoing challenges and questions discussed in this invited review relate to the best population to treat, optimal timing and duration of treatment, and potential barriers to implementation due to evolving knowledge and guidelines. IMPACT STATEMENT: Prophylactic low-dose hydrocortisone improves survival without BPD in infants born extremely preterm. Recent real-world data generally confirm the benefits observed in clinical trials, even with additional potential benefits and without increased adverse events. Unanswered questions remain about optimal timing and duration of treatment, and potential barriers to implementation due to evolving knowledge and guidelines.

Impact of postnatal steroids on peripheral avascular retina and severity of retinopathy of prematurity

BACKGROUND

We investigated the role of postnatal steroids on the severity of retinopathy of prematurity (ROP) and its impact on peripheral avascular retina (PAR).

METHODS

A retrospective cohort study of infants born at ≤32 weeks gestation and/or birth weight ≤1500 g. Demographics, the dose and duration of steroid treatment, and age when full retinal vascularization occurred were collected. The primary outcomes were the severity of ROP and time to full vascularization of the retina.

RESULTS

A total of 1695 patients were enrolled, 67% of whom received steroid therapy. Their birth weight was 1142 ± 396 g and gestational age was 28.6 ± 2.7 weeks. The total hydrocortisone-equivalent dose prescribed was 28.5 ± 74.3 mg/kg. The total days of steroid treatment were 8.9 ± 35.1 days. After correction for major demographic differences, infants who received a higher cumulative dose of steroids for a longer duration had a significantly increased incidence of severe ROP and PAR (P < 0.001). For each day of steroid treatment, there was a 3.2% increase in the hazard of the severe form of ROP (95% CI: 1.022-1.043) along with 5.7% delay in achieving full retinal vascularization (95% CI: 1.04-1.08) (P < 0.001).

CONCLUSION

Cumulative dose and duration of postnatal steroid use were independently associated with the severity of ROP and PAR. Thus, postnatal steroids should be used very prudently.

IMPACT

We report ROP outcomes in a large cohort of infants from two major healthcare systems where we have studied the impact of postnatal steroids on the severity of ROP, growth, and development of retinal vessels. After correcting our data for three major outcome measures, we show that high-dose postnatal steroids used for a prolonged duration of time are independently associated with severe ROP and delay in retinal vascularization. Postnatal steroids impact the visual outcomes of VLBW infants significantly, so their clinical use needs to be moderated.

Glucocorticoid signature of preterm infants developing bronchopulmonary dysplasia

BACKGROUND

Systemic inflammation plays a key role in the development of bronchopulmonary dysplasia (BPD). Cortisol is known to dampen inflammation. However, adrenal function following preterm birth is characterized by insufficient cortisol levels for the degree of inflammation, and a relative abundancy of cortisol precursors. We investigated whether this pattern could contribute to the development of BPD in preterm infants born <30 weeks of gestation.

METHODS

Cortisol, cortisone, 17-OH progesterone (17-OHP) and 11-deoxycortisol were measured in serum obtained at postnatal days 1, 3, 7, 14 and 28, using liquid-chromatography-tandem-mass-spectrometry. The presence of BPD was ascertained at 36 weeks postmenstrual age.

RESULTS

Sixty-five infants were included for analysis, of whom 32 (49%) developed BPD. Preterm infants developing BPD, as compared to those without BPD, had higher levels of 17-OHP, 11-deoxycortisol and cortisone relative to cortisol in their first week of life, but not at birth or beyond day 7.

CONCLUSION

Preterm infants developing BPD had higher levels of cortisol precursors and cortisone relative to cortisol in their first week of life than infants without BPD. These findings suggest that BPD is preceded by an activated hypothalamus-pituitary-adrenal axis that could not meet the high cortisol demands, which may predispose to inflammation and BPD.

IMPACT

Relative adrenal insufficiency is common in the first weeks after preterm birth, resulting in insufficient cortisol production for the degree of inflammation and a relative abundance of cortisol precursors; Whether this pattern contributes to the development of bronchopulmonary dysplasia (BPD) is not fully elucidated, since most studies focused on cortisol levels; Preterm infants developing BPD had higher levels of cortisol precursors and cortisone relative to cortisol in the first week of life, suggestive of a hypothalamus-pituitary-adrenal-axis activation during BPD development which cannot meet the high cortisol demands in tissues; This glucocorticoid pattern is likely to dispose to inflammation and BPD.

Ozone-dependent increases in lung glucocorticoids and macrophage response: Effect modification by innate stress axis function

Although considerable inter-individual variability exists in health effects associated with air pollutant exposure, underlying reasons remain unclear. We examined whether innate differences in stress axis function modify lung glucocorticoid and macrophage responses to ozone (O3). Highly-stress responsive Fischer (F344) and less responsive Lewis (LEW) rats were exposed for 4 h by nose-only inhalation to air or O3 (0.8 ppm). Ozone increased corticosterone recovered by bronchoalveolar lavage in both strains (F344 > LEW). Higher corticosterone in F344 was associated with a blunted response to O3 of macrophage pro-inflammatory genes compared to LEW. Pharmacological inhibition of O3-dependent corticosterone production in F344 enhanced the inflammatory gene response to O3, mimicking the LEW phenotype. Examination of potential impacts of glucocorticoids on macrophage function using a human monocyte-derived macrophage cell line (THP-1) showed that cortisol modified phagocytosis in a macrophage phenotype-dependent manner. Overall, our data implicate endogenous glucocorticoids in the regulation of pulmonary macrophage responses to O3.

Association between Baseline Cortisol Serum Concentrations and the Effect of Prophylactic Hydrocortisone in Extremely Preterm Infants

OBJECTIVE

To define nomograms of serum cortisol values before 24 hours of postnatal life for extremely preterm infants and determine whether baseline cortisol values affect the benefit/risk ratio of prophylactic hydrocortisone to improve survival without bronchopulmonary dysplasia (BPD).

STUDY DESIGN

We performed a predefined secondary analysis of the multicenter randomized controlled PREMILOC trial that included inborn infants delivered before 28 weeks of gestation. Nomograms of baseline serum cortisol values measured in 325 enrolled patients were determined for male and female neonates and correlated to perinatal events. BPD-free survival and severe adverse events were analyzed in placebo and hydrocortisone groups according to the cortisol z score in multivariate logistic regression models.

RESULTS

Increased cortisol levels measured before 24 hours following birth were associated with a significantly higher chance of BPD-free survival only in placebo-treated infants (aOR [95% CI] 1.57 [1.08-2.27], P = .02) based on sex-specific nomograms for baseline cortisol levels. The cortisol z score for infants treated with prophylactic hydrocortisone predicted a risk of high-grade intraventricular hemorrhage (aOR [95% CI] 1.82 [1.06-3.15], P = .03) and spontaneous intestinal perforation (aOR [95% CI] 4.81 [1.34-17.22], P = .02).

CONCLUSIONS

We found no predictive value of baseline cortisol levels for BPD-free survival in infants born extremely preterm treated with hydrocortisone. However, high cortisol levels early after birth were associated with a greater risk of severe intraventricular hemorrhage and spontaneous intestinal perforation in infants treated with hydrocortisone and, therefore, a lower benefit/risk ratio for the treatment.

TRIAL REGISTRATION

EudraCT 2007-002041-20, ClinicalTrial.gov: NCT00623740.

Assessment of adrenal function at birth using adrenal glucocorticoid precursor to product ratios to predict short-term neonatal outcomes

BACKGROUND

Most neonatal outcomes in neonates are related to normal adrenal gland function. Assessment of adrenal function in a sick preterm neonate remains a challenge, thus we hypothesized that adrenal steroid precursors to their product ratios have a direct relationship with neonatal outcomes.

METHODS

We studied demographics of pregnancy and neonatal outcomes in 99 mother-infant pairs (24-41 weeks) and assayed 7 glucocorticoid precursors in the cortisol biosynthesis/degradation pathway. We correlated antenatal factors and short-term neonatal outcomes with these precursors and their ratios to assess maturity of individual enzymes.

RESULTS

We found no correlation between cortisol levels with antenatal factors and outcomes. Antenatal steroid use impacted several cortisol precursors. 17-OH pregnenolone-to-cortisol ratio at birth was the best predictor of short-term neonatal outcomes, such as hypotension, RDS, IVH and PDA. A cord blood 17-OH pregnenolone:cortisol ratio of <0.21 predicts which neonate will have a normal outcome with a high sensitivity and specificity.

CONCLUSIONS

Maternal factors and antenatal steroids impact neonatal adrenal function and leads to maturation of adrenal function. 17-OH pregnenolone:cortisol ratio and not cortisol is the best predictor of adrenal function. Adrenal function can be assessed by evaluating the profile of adrenal steroids.

Hydrocortisone and bronchopulmonary dysplasia: variables associated with response in premature infants

OBJECTIVE

The primary objective was to evaluate hydrocortisone's efficacy for decreasing respiratory support in premature infants with developing bronchopulmonary dysplasia (BPD). Secondary objectives included assessment of the impact of intrauterine growth restriction (IUGR), maternal history of chorioamnionitis, side effects and route of administration associated with hydrocortisone's efficacy. Dexamethasone as second-line treatment to decrease respiratory support was reviewed.

METHODS

Retrospective chart review of preterm infants requiring respiratory support receiving hydrocortisone.

RESULTS

A total of 48 patients were included. Successful extubation was achieved in 50% of intubated patients after hydrocortisone treatment with no major complications. In our small study, history of maternal chorioamnionitis, IUGR or route of administration did not affect the response. Rescue dexamethasone after hydrocortisone therapy was ineffective in the ten patients who failed extubation following hydrocortisone.

CONCLUSION

Hydrocortisone is effective in decreasing respiratory support in patients with developing BPD without major complications. Randomized studies are warranted to confirm our findings.

Late-onset glucocorticoid-responsive circulatory collapse in premature infants

Late-onset glucocorticoid-responsive circulatory collapse (LGCC) in infants is characterized by sudden onset of hypotension and/or oliguria, which is resistant to volume expanders and inotropes but responds rapidly to intravenous glucocorticoids. LGCC occurs after the first week of life mainly in relatively stable very low birth weight (VLBW) infants. In Japan, the incidence of LGCC is reported to be 8%. Relative adrenal insufficiency (AI) is considered the most likely cause of LGCC, but its detailed pathophysiology remains unclear. Intrinsic and extrinsic factors may affect the pathophysiological mechanism. LGCC should be recognized as one of the high-risk complications in VLBW infants and managed promptly and properly, because if it is not, it may cause life-long neurological problems. To diagnose relative AI, an accurate evaluation of adrenal function is necessary; however, the interpretation of basal serum cortisol levels is difficult in preterm infants after 7 days of life. To recognize LGCC, it is recommended that blood pressure and urine volume be carefully monitored, even outside of the transitional period. If no underlying causes are documented or volume expansion and inotropic support fail, intravenous hydrocortisone should be initiated, and an additional dose of hydrocortisone is required when the response is inadequate. There are few reports to verify or characterize LGCC and this phenomenon has not been recognized worldwide to date. This review summarizes the current knowledge about LGCC in premature infants and evaluates the most significant new findings regarding its pathophysiology, treatment, and prognosis.

Cortisol production in preterm infants with or without late-onset adrenal insufficiency of prematurity: A prospective observational study

BACKGROUND

Immature adrenocortical function in preterm infants may cause inadequate production of cortisol under stress, resulting in adrenal insufficiency of prematurity (AOP). The objective of this study is to compare cortisol production in preterm infants with and without late-onset AOP.

METHODS

Of 27 preterm infants born at less than 32 weeks gestation, cortisol production was analyzed in those who did (patients, group P) and did not (controls, group C) eventually develop late-onset AOP. Blood samples were prospectively collected every two weeks after birth, and steroid hormone concentrations in the pathway to cortisol production were measured retrospectively.

RESULTS

We restricted the initial subjects to infants with gestation less than 29 weeks to adjust for confounding factors, culminating in matched infants in groups P (n = 8) and C (n = 11). The cortisol concentrations did not differ between the groups before AOP onset (P = 0.20), but the total concentrations of precursors for cortisol were higher in group P (P < 0.0001). The total concentrations of precursors in group C were inversely correlated with postmenstrual age (ρ = -0.38, P < 0.01). The pattern of changes in total concentrations of precursors differed between the groups (P < 0.05).

CONCLUSION

Adrenal cortex maturity in preterm infants develops in parallel with postmenstrual age. Infants with late-onset AOP have undeveloped maturation of adrenocortical function after birth.

CLINICAL TRIAL REGISTRATION

UMIN000022453.

Prophylactic postnatal corticosteroids: Early hydrocortisone

Inflammation is a key contributor to the pathogenesis of bronchopulmonary dysplasia (BPD) in preterm infants, and cortisol plays a central role in controlling inflammation. Insufficient cortisol limits the ability of the sick newborn to handle stress and inhibit pulmonary inflammation. Evidence of lower cortisol and lower response to adrenocorticotropic hormone in infants subsequently developing BPD led to studies of early low-dose hydrocortisone to prevent BPD. Based on four randomised clinical trials enrolling almost 1000 extremely preterm infants, prophylaxis of early adrenal insufficiency with low-dose hydrocortisone significantly decreased BPD and mortality, as well as medical treatment for a patent ductus arteriosus. An increase in late-onset sepsis reported in the most immature infants had no adverse effect on mortality or neurodevelopmental outcomes. There was no increase in gastrointestinal perforation in the absence of indomethacin. The demonstrated beneficial effects of early low-dose hydrocortisone make a strong case for its use in extremely preterm infants at high risk for BPD.

Effect of Prophylaxis for Early Adrenal Insufficiency Using Low-Dose Hydrocortisone in Very Preterm Infants: An Individual Patient Data Meta-Analysis

OBJECTIVE

To assess the effect of prophylaxis for early adrenal insufficiency using low-dose hydrocortisone on survival without bronchopulmonary dysplasia (BPD) in very preterm infants using an individual patient data meta-analysis.

STUDY DESIGN

All existing randomized controlled trials testing the efficacy of the prophylaxis of early adrenal insufficiency using low-dose hydrocortisone on survival without BPD were considered for inclusion when data were available. The primary outcome was the binary variable survival without BPD at 36 weeks of postmenstrual age.

RESULTS

Among 5 eligible studies, 4 randomized controlled trials had individual patient data available (96% of participants identified; n = 982). Early low-dose hydrocortisone treatment for 10-15 days was associated with a significant increase in survival without BPD (OR, 1.45; 95% CI, 1.11-1.90; P = .007; I² = 0%), as well as with decreases in medical treatment for patent ductus arteriosus (OR, 0.72; 95% CI, 0.56-0.93; P = .01; I² = 0%) and death before discharge (OR, 0.70; 95% CI, 0.51-0.97; P = .03; I² = 0%). The therapy was associated with an increased risk of spontaneous gastrointestinal perforation (OR, 2.50; 95% CI, 1.33-4.69; P = .004; I² = 31.9%) when hydrocortisone was given in association with indomethacin exposure. The incidence of late-onset sepsis was increased in infants exposed to hydrocortisone (OR, 1.34; 95% CI, 1.02-1.75; P = .04; I² = 0%), but no adverse effects were reported for either death or 2-year neurodevelopmental outcomes as assessed in an aggregate meta-analysis.

CONCLUSIONS

This individual patient data meta-analysis showed that early low-dose hydrocortisone therapy is beneficial for survival without BPD in very preterm infants.

Stress axis variability is associated with differential ozone-induced lung inflammatory signaling and injury biomarker response

Ozone (O₃), a ubiquitous urban air pollutant, causes adverse pulmonary and extrapulmonary effects. A large variability in acute O₃-induced effects has been observed; however, the basis for interindividual differences in susceptibility is unclear. We previously demonstrated a role for the hypothalamic-pituitary-adrenal (HPA) stress axis and glucocorticoid response in acute O₃ toxicity. Glucocorticoids have important anti-inflammatory actions, and have been shown to regulate lung inflammatory responses. We hypothesised that a hyporesponsive HPA axis would be associated with greater O₃-dependent lung inflammatory signaling. Two genetically-related rat strains with known differences in stress axis reactivity, highly-stress responsive Fischer (F344) and less responsive Lewis (LEW), were exposed for 4 h by nose-only inhalation to clean air or 0.8 ppm O₃, and euthanized immediately after exposure. As expected, baseline (air-exposed) plasma corticosterone was significantly lower in the hypo-stress responsive LEW. Although O₃ exposure increased plasma corticosterone in both strains, corticosterone remained significantly lower in LEW when compared to F334. LEW exhibited greater O₃-induced inflammatory cytokine/chemokine signaling compared to F344, consistent with the lower corticosterone levels. Since we observed strain-specific differences in inflammatory signaling, we further investigated injury biomarkers (total protein, albumin and lactate dehydrogenase). Although the hyper-responsive F344 exhibited lower inflammatory signaling in response to O₃ compared with LEW, they had greater levels of lung injury biomarkers. Our results indicate that stress axis variability is associated with differential O₃-induced lung toxicity. Given the large variability in stress axis reactivity among humans, stress axis regulation could potentially be a determining factor underlying O₃ sensitivity.

Alterations of adrenal steroidomic profiles in preterm infants at birth

OBJECTIVE

Preterm infants have relative adrenal and kidney immaturity. Recently, we linked their urine sodium loss to a hypoaldosteronism at variance with an appropriate stimulation of the renin-angiotensin system. To investigate this defective aldosterone secretion, we analyse the biosynthesis pathways of adrenal steroids in neonates according to gestational age (GA).

DESIGN

Multicentre study (Premaldo) including 152 neonates classified into three groups: group 1 (very preterm (VPT)): <33  gestational weeks (GW); group 2 (preterm (PT)): 33-36 GW and group 3 (term (T)): ≥GW.

METHOD

Steroidomic profiles of mineralocorticoids, glucocorticoids and adrenal androgens were established from umbilical cord at birth (n=152) and peripheral blood at day 3 (n=70) using a recently developed liquid chromatography mass spectrometry method (LC-MS/MS). The enzymatic activity of each biosynthesis step was estimated by the product-to-substrate ratio.

RESULTS

At birth, VPT infants exhibit a global defect in adrenal steroid synthesis pathways leading to lower levels of aldosterone, cortisol and androstenedione than in term infants. This defect was strongly related to GA. On day 3, steroid precursors (progesterone, 11-deoxycorticosterone (DOC), 17-hydroxyprogesterone(17-OH-P) and 11-deoxycortisol (S)) were higher in VPT and negatively correlated with GA. Despite of precursors' accumulation, aldosterone and cortisol were similar in the three groups. At birth and day 3, a low cortisol/11-deoxycortisol ratio was found in preterm infants, suggesting an 11-beta-hydroxylase activity (CYP11B1) deficiency.

CONCLUSIONS

At birth, VPT infants exhibit a global deficit in mineralocorticoids, glucocorticoids and adrenal androgens that attenuates on day 3 of life. Steroid profiling using LC-MS/MS provides evidence for a partial defect in 11-hydroxylase along with prematurity.

Hyperdehydroepiandrosterone in neonates with hypoxic ischemic encephalopathy and circulatory collapse

BACKGROUND

Circulatory collapse is a very common complication of the critical illnesses in neonates including neonates with hypoxic ischemic encephalopathy; it can be the end result and cause of death of several conditions. Often, despite treatment with fluid resuscitation and vasopressor agents, circulatory collapse persist, and blood pressure can remain critically low, compromising adequate blood flow to vital organs and brain. Low blood pressure has been associated with increased mortality.

METHOD

To investigate adrenal function in newborn infants who suffer from circulatory collapse during hypoxic ischemic encephalopathy. A total of 30 infants were analyzed in the study: 15 neonates in group A (neonates had hypoxic ischemic encephalopathy with vasopressor resistant hypotension) and 15 neonates in group B (neonates with hypoxic ischemic encephalopathy without vasopressor resistant hypotension). All the studied patients were subjected to history, examinations and laboratory investigation including serum cortisol concentrations and cortisol precursor's levels.

RESULTS

The cortisol concentrations did not differ significantly between the two groups: (12.9 ± 4.3) μg/dL and (12.1 ± 2.4) μg/dL in group A and group B, respectively. There are highly significant differences between groups A and B regarding Dehydroepiandrosterone (342.1 ± 101.3) μg/dL, (33.4 ± 16.5) μg/dL, respectively.

CONCLUSION

In this study, we noticed that cortisol concentrations did not differ between both groups in contrast to the expectation that neonates with critical illnesses should have higher cortisol concentrations than normal neonates. However, the marked increase in dehydroepiandrosterone DHEA may cause decrease cortisol function, so those neonates having accumulation of dehydroepiandrosterone may suffer from manifestation of adrenal insufficiency and vasopressor resistant hypotension in spite of normal cortisol level.

Associations Between Hormonal Biomarkers and Cognitive, Motor, and Language Developmental Status in Very Low Birth Weight Infants

BACKGROUND

Male infants are more prone to health problems and developmental delays than female infants.

OBJECTIVES

On the basis of theories of gender differences in brain development and social relationships, we explored associations between testosterone and cortisol levels with infant cognitive, motor, and language development ("infant development") in very low birth weight (VLBW) infants, controlling for mother-infant interactions, characteristics of mothers and infants, and days of saliva collection after birth.

METHODS

A total of 62 mother-VLBW infant pairs were recruited from the newborn intensive care unit of a tertiary medical center in the Southeast United States. Data were collected through infant medical record review, biochemical measurement, observation of mother-infant interactions, and standard questionnaires. Infant development was assessed at 6 months corrected age (CA), and mother-infant interactions were observed at 3 and 6 months CA.

RESULTS

General linear regression with separate analyses for each infant gender showed that high testosterone levels were positively associated with language development of male infants after controlling for mother-infant interactions and other covariates, whereas high cortisol levels were negatively associated with motor development of female infants after controlling for mother-infant interactions.

CONCLUSIONS

Steroid hormonal levels may well be more fundamental factors for assessing infant development than infant gender or mother-infant interactions at 6 months CA.

Steroid use for refractory hypotension in congenital diaphragmatic hernia

PURPOSE

Guidelines for diagnosis and treatment of adrenal insufficiency (AI) in newborns with congenital diaphragmatic hernia (CDH) are poorly defined.

METHODS

From 2002 to 2016, 155 infants were treated for CDH at our institution. Patients with shock refractory to vasopressors (clinically diagnosed AI) were treated with hydrocortisone (HC). When available, random cortisol levels <10 μg/dL were considered low. Outcomes were compared between groups.

RESULTS

Hydrocortisone was used to treat AI in 34% (53/155) of patients. That subset of patients was demonstrably sicker, and mortality was expectedly higher for those treated with HC (37.7 vs. 17.6%, p = 0.0098). Of the subset of patients with random cortisol levels measured before initiation of HC, 67.7% (21/31) had low cortisol levels. No significant differences were seen in survival between the high and low groups, but mortality trended higher in patients with high cortisol levels that received HC. After multivariate analysis, duration of HC stress dose administration was associated with increased risk of mortality (OR 1.11, 95% CI 1.02-1.2, p = 0.021), and total duration of HC treatment was associated with increased risk of sepsis (OR 1.04, 95% CI 1.005-1.075, p = 0.026).

CONCLUSION

AI is prevalent amongst patients with CDH, but prolonged treatment with HC may increase risk of mortality and sepsis.

Management of Neonatal Hypotension

Hypotension is a common problem in neonates with complex underlying pathophysiology. Although treatment of low blood pressure is common, clinicians must use all available information to target neonates with compromised perfusion. Pharmacotherapy should be tailored to the specific physiologic perturbations of the individual neonate. Dopamine is the most commonly utilized agent and may be the most appropriate agent for septic shock with low diastolic blood pressure. However, alternative therapies should be considered for other etiologies of hypotension, including milrinone and vasopressin for persistent pulmonary hypertension of the newborn and dobutamine for patent ductus arteriosus. Additional studies are required to refine the approach to neonatal hypotension and document the long-term outcomes of treated neonates.

Cortisol precursors in neonates with vasopressor-resistant hypotension in relationship to demographic characteristics

OBJECTIVE

To correlate between cortisol precursors in neonates with vasopressor resistant hypotension and demographic characteristics.

METHODS

We investigated 48 neonates with vasopressor-resistant hypotension. Gestation at birth ranged from 34 to 42 weeks and postnatal age from 4 to 14 days. Cortisol and precursor steroids were measured soon after the onset of volume expansion and inotropes for treatment of shock. Their concentrations were determined using liquid chromatography/mass spectrometry.

RESULTS

In neonates with vasopressor-resistant hypotension, the serum levels of cortisol were within normal nonstress range. There was a strong negative linear association between postnatal age and dehydroepiandrosterone level (r = -0.50, p < .01), which decreased with neonatal age. In addition, there was a significant positive association between gestational age at birth and 17-hydroxy-pregnenolone (r = 0.33, p = .02). No further significant associations were evident between the neonatal weight, duration of gestation or gender and of the levels of cortisol or the other steroids (p > .05). The cause of therapy-resistant hypotension did not appear to influence the steroid levels.

CONCLUSIONS

Cortisol stress response is absent in these severely ill late preterm and term infants. This may be due to inhibition of the distal pathway of cortisol synthesis.

Medical morbidities and DNA methylation of NR3C1 in preterm infants

BACKGROUND

Although there are no accepted "normal" levels of circulating cortisol in preterm infants, critically ill preterm infants show lower cortisol levels than healthy preterm infants. The regulation of cortisol reactivity by epigenetic changes in glucocorticoid receptor gene (NR3C1) expression has been demonstrated. This study aims to examine the relationship between medical morbidities in preterm infants and DNA methylation of NR3C1.

METHODS

Pyrosequencing was used to determine DNA methylation in CpG sites 1-4 of promoter region 1F of NR3C1. Cluster analysis placed 67 preterm infants born <1,500 g into groups based on medical morbidities. The DNA methylation pattern was compared across groups.

RESULTS

Cluster analysis identified a high medical risk cluster and a low medical risk cluster. A Mann-Whitney U-test showed lower methylation at CpG1 for infants in the high-risk group (M = 0.336, SE = 0.084) than infants in the low-risk group (M = 0.617, SE = 0.109, P = 0.032). The false discovery rate was low (q = 0.025). Cohen's D effect size was moderate (0.525).

CONCLUSION

Decreased DNA methylation of CpG1 of NR3C1 in high-risk infants may allow for increased binding of transcription factors involved in the stress response, repair and regulation of NR3C1. This may ensure healthy growth in high-risk preterm infants over increasing cortisol levels.

Adrenocortical insufficiency and refractory hypotension in preterm infants

Preterm, very low birthweight (VLBW) infants are prone to life-threatening hypotension secondary to hypothalamic-pituitary-adrenal axis immaturity, resulting in adrenocortical insufficiency. Clinical presentations of inotrope-resistant refractory hypotension are usually evident, but interpretation of serum cortisol may pose much difficulty to front-line neonatologists. This review examines the salient pathophysiology of adrenocortical insufficiency in the immediate postnatal period, characterises its endocrinological abnormalities, and describes the typical and variant clinical presentations. Based on existing evidence, a practical scheme is proposed for logical interpretation of circulating cortisol levels and management of inotrope-resistant refractory hypotension in VLBW infants.

Untargeted Metabolomic Analysis of Amniotic Fluid in the Prediction of Preterm Delivery and Bronchopulmonary Dysplasia

OBJECTIVE

Bronchopulmonary dysplasia (BPD) is a serious complication associated with preterm birth. A growing body of evidence suggests a role for prenatal factors in its pathogenesis. Metabolomics allows simultaneous characterization of low molecular weight compounds and may provide a picture of such a complex condition. The aim of this study was to evaluate whether an unbiased metabolomic analysis of amniotic fluid (AF) can be used to investigate the risk of spontaneous preterm delivery (PTD) and BPD development in the offspring.

STUDY DESIGN

We conducted an exploratory study on 32 infants born from mothers who had undergone an amniocentesis between 21 and 28 gestational weeks because of spontaneous preterm labor with intact membranes. The AF samples underwent untargeted metabolomic analysis using mass spectrometry combined with ultra-performance liquid chromatography. The data obtained were analyzed using multivariate and univariate statistical data analysis tools.

RESULTS

Orthogonally Constrained Projection to Latent Structures-Discriminant Analysis (oCPLS2-DA) excluded effects on data modelling of crucial clinical variables. oCPLS2-DA was able to find unique differences in select metabolites between term (n = 11) and preterm (n = 13) deliveries (negative ionization data set: R2 = 0.47, mean AUC ROC in prediction = 0.65; positive ionization data set: R2 = 0.47, mean AUC ROC in prediction = 0.70), and between PTD followed by the development of BPD (n = 10), and PTD without BPD (n = 11) (negative data set: R2 = 0.48, mean AUC ROC in prediction = 0.73; positive data set: R2 = 0.55, mean AUC ROC in prediction = 0.71).

CONCLUSIONS

This study suggests that amniotic fluid metabolic profiling may be promising for identifying spontaneous preterm birth and fetuses at risk for developing BPD. These findings support the hypothesis that some prenatal metabolic dysregulations may play a key role in the pathogenesis of PTD and the development of BPD.

Fetal and Neonatal HPA Axis

Stress is an integral part of life. Activation of the hypothalamus-pituitary-adrenal (HPA) axis in the adult can be viewed as mostly adaptive to restore homeostasis in the short term. When stress occurs during development, and specifically during periods of vulnerability in maturing systems, it can significantly reprogram function, leading to pathologies in the adult. Thus, it is critical to understand how the HPA axis is regulated during developmental periods and what are the factors contributing to shape its activity and reactivity to environmental stressors. The HPA axis is not a passive system. It can actively participate in critical physiological regulation, inducing parturition in the sheep for instance or being a center stage actor in the preparation of the fetus to aerobic life (lung maturation). It is also a major player in orchestrating mental function, metabolic, and cardiovascular function often reprogrammed by stressors even prior to conception through epigenetic modifications of gametes. In this review, we review the ontogeny of the HPA axis with an emphasis on two species that have been widely studied-sheep and rodents-because they each share many similar regulatory mechanism applicable to our understanding of the human HPA axis. The studies discussed in this review should ultimately inform us about windows of susceptibility in the developing brain and the crucial importance of early preconception, prenatal, and postnatal interventions designed to improve parental competence and offspring outcome. Only through informed studies will our public health system be able to curb the expansion of many stress-related or stress-induced pathologies and forge a better future for upcoming generations.

Neurobehavior related to epigenetic differences in preterm infants

Preterm birth is associated with medical problems affecting the neuroendocrine system, altering cortisol levels resulting in negative effects on newborn neurobehavior. Newborn neurobehavior is regulated by DNA methylation of NR3C1 and HSD11B2.

AIM

Determine if methylation of HSD11B2 and NR3C1 is associated with neurobehavioral profiles in preterm infants.

PATIENTS & METHODS

Neurobehavior was measured before discharge from the hospital in 67 preterm infants. Cheek swabs were collected for DNA extraction.

RESULTS

Infants with the high-risk neurobehavioral profile showed more methylation than infants with the low-risk neurobehavioral profile at CpG3 for NR3C1 and less methylation of CpG3 for HSD11B2. Infants with these profiles were more likely to have increased methylation of NR3C1 and decreased methylation of HSD11B2 at these CpG sites.

CONCLUSION

Preterm birth is associated with epigenetic differences in genes that regulate cortisol levels related to high-risk neurobehavioral profiles.

Associations of Maternal and Infant Testosterone and Cortisol Levels With Maternal Depressive Symptoms and Infant Socioemotional Problems

This study examined the associations of testosterone and cortisol levels with maternal depressive symptoms and infant socioemotional (SE) problems that are influenced by infant gender. A total of 62 mothers and their very-low-birth weight (VLBW) infants were recruited from a neonatal intensive care unit at a tertiary medical center in the southeast United States. Data were collected at three time points (before 40 weeks' postmenstrual age [PMA] and at 3 months and 6 months of age corrected for prematurity). Measures included infant medical record review, maternal interview, biochemical assays of salivary hormone levels in mother-VLBWinfant pairs, and standard questionnaires. Generalized estimating equations with separate analyses for boys and girls showed that maternal testosterone level was negatively associated with depressive symptoms in mothers of boys, whereas infant testosterone level was negatively associated with maternal report of infant SE problems in girls after controlling for characteristics of mothers and infants and number of days post birth of saliva collection. Not surprisingly, the SE problems were positively associated with a number of medical complications. Mothers with more depressive symptoms reported that their infants had more SE problems. Mothers with higher testosterone levels reported that girls, but not boys, had fewer SE problems. In summary, high levels of testosterone could have a protective role for maternal depressive symptoms and infant SE problems. Future research need to be directed toward clinical application of these preliminary results.

Comparison of cortisol samples in the first two weeks of life in preterm infants

BACKGROUND

Growing literature on negative childhood stress emphasizes the need to understand cortisol values from varying biomarker samples.

OBJECTIVE

This work aimed to examine cortisol samples for usability, associations, and individual stability in neonates.

SUBJECTS

The sample consisted of preterm infants (n=31).

MATERIALS AND METHODS

Analyses on cortisol collected from cord blood and from saliva and urine samples on days 1, 7, and 14 included Spearman correlations and paired t-tests.

RESULTS

Usability rates were 80.6% (cord blood), 85.9% (saliva), and 93.5% (urine). Salivary and urinary cortisol levels had significant correlation on day 1 only (p=0.004). Significant differences in individual stability of cortisol concentrations existed except in urine on days 1 and 7 and in saliva on days 7 and 14.

CONCLUSIONS

Usability was highest for urine samples. We found little correlation between cortisol sample levels at each time; individual stability of cortisol concentrations was minimal. Interpretation of cortisol findings in all studies should be performed cautiously.

Behaviour problems and cortisol levels in very-low-birth-weight children

Abstract Background. There are still diverging results concerning the behaviour of children with very-low-birth-weight (VLBW) and they have been questioned to display different levels of stress hormone than normal-birth-weight (NBW) children. Aims. This study examined behaviour and the stress hormone cortisol in children with VLBW at the ages of 7 and 9 years compared with children with NBW. Results. Fifty-one VLBW and 50 NBW children were studied with the Child Behavior Checklist. Cortisol rhythm was measured through saliva samples three times a day for 2 days. VLBW children displayed more behavioural problems than NBW children, specifically social and attention problems, although still within normal ranges. They showed lower cortisol levels both at 7 and 9 years of age. No strong association between behaviour and cortisol levels was shown. Conclusion. VLBW children display more behaviour problems compared with NBW children but both groups score are within the normal range. Down-regulation of their hypothalamic-pituitary-adrenal (HPA) function in terms of lower cortisol levels is also noted.

Population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension

OBJECTIVES

To determine the population pharmacokinetics of unbound hydrocortisone in critically ill neonates and infants receiving IV hydrocortisone for treatment of vasopressor-resistant hypotension and to identify patient-specific sources of pharmacokinetic variability.

DESIGN

Prospective observational cohort study.

SETTING

Level 3 neonatal ICU.

PATIENTS

Sixty-two critically ill neonates and infants receiving IV hydrocortisone as part of standard of care for the treatment of vasopressor-resistant hypotension: median gestational age 28 weeks (range, 23-41), median weight 1.2 kg (range, 0.5-4.4), and 29 females.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Unbound baseline cortisol and postdose hydrocortisone concentrations measured from blood samples being drawn for routine laboratory tests. A one-compartment model best described the data. Allometric weight and postmenstrual age were significant covariates on unbound hydrocortisone clearance and volume of distribution. Final population estimates for clearance, volume of distribution, and baseline cortisol concentration were 20.2 L/hr, 244 L, and 1.37 ng/mL, respectively. Using the median weight and postmenstrual age of our subjects (i.e., 1.2 kg and 28 wk) in the final model, the typical unbound hydrocortisone clearance and volume of distribution were 1.0 L/hr and 4.2 L, respectively. The typical half-life for unbound hydrocortisone was 2.9 hours. A sharp and continuous increase in unbound hydrocortisone clearance was observed at 35 weeks postmenstrual age.

CONCLUSIONS

We report the first pharmacokinetic data for unbound hydrocortisone, the pharmacologically active moiety, in critically ill neonates and infants with vasopressor-resistant hypotension. Unbound hydrocortisone clearance increased with body weight and was faster in children with an older postmenstrual age. Unbound hydrocortisone clearance increased sharply at 35 weeks postmenstrual age and continued to mature thereafter. This study lays the groundwork for evaluating unbound hydrocortisone exposure-response relationships and drawing definitive conclusions about the dosing of IV hydrocortisone in critically ill neonates and infants with vasopressor-resistant hypotension.

Adrenocortical sensitivity to ACTH in neonatal rats: correlation of corticosterone responses and adrenal cAMP content

A coordinated hypothalamic-pituitary-adrenal axis response is important for the survival of newborns during stress. We have previously shown that prior to postnatal day (PD) 5, neonatal rats exposed to hypoxia (one of the most common stressors effecting premature neonates) exhibit a large corticosterone response with a minimal increase in immunoassayable plasma ACTH and without a detectable increase in adrenal cAMP content (the critical second messenger). To explore the phenomenon of ACTH-stimulated steroidogenesis in the neonate, we investigated the adrenal response to exogenous ACTH in the normoxic neonatal rat. Rat pups at PD2 and PD8 were injected intraperitoneally with porcine ACTH at low, moderate, or high doses (1, 4, or 20 μg/kg body wt). Trunk blood and whole adrenal glands were collected at baseline (before injection) and 15, 30, or 60 min after the injection. ACTH stimulated corticosterone release in PD2 and PD8 pups. In PD2 pups, plasma corticosterone at baseline and during the response to ACTH injection was greater than values measured in PD8 pups, despite lower adrenal cAMP content in PD2 pups. Specifically, the low and moderate physiological ACTH doses produced a large corticosterone response in PD2 pups without a change in adrenal cAMP content. At extremely high, pharmacological levels of plasma ACTH in PD2 pups (exceeding 3,000 pg/ml), an increase in adrenal cAMP was measured. We conclude that physiological increases in plasma ACTH may stimulate adrenal steroidogenesis in PD2 pups through a non-cAMP-mediated pathway.

Hypotension following patent ductus arteriosus ligation: the role of adrenal hormones

OBJECTIVE

To test the hypothesis that an impaired adrenal response to stress might play a role in the hypotension that follows patent ductus arteriosus (PDA) ligation.

STUDY DESIGN

We performed a multicenter study of infants born at <32 weeks' gestation who were about to undergo PDA ligation. Serum adrenal steroids were measured 3 times: before and after a cosyntropin (1.0 μg/kg) stimulation test (performed before the ligation), and at 10-12 hours after the ligation. A standardized approach for diagnosis and treatment of postoperative hypotension was followed at each site. A modified inotrope score (1 × dopamine [μg/kg/min] + 1 × dobutamine) was used to monitor the catecholamine support an infant received. Infants were considered to have catecholamine-resistant hypotension if their greatest inotrope score was >15.

RESULTS

Of 95 infants enrolled, 43 (45%) developed hypotension and 14 (15%) developed catecholamine-resistant hypotension. Low postoperative cortisol levels were not associated with the overall incidence of hypotension after ligation. However, low cortisol levels were associated with the refractoriness of the hypotension to catecholamine treatment. In a multivariate analysis: the OR for developing catecholamine-resistant hypotension was OR 36.6, 95% CI 2.8-476, P = .006. Low cortisol levels (in infants with catecholamine-resistant hypotension) were not attributable to adrenal immaturity or impairment; their cortisol precursor concentrations were either low or unchanged, and their response to cosyntropin was similar to infants without catecholamine-resistant hypotension.

CONCLUSION

Infants with low cortisol concentrations after PDA ligation are likely to develop postoperative catecholamine-resistant hypotension. We speculate that decreased adrenal stimulation, rather than an impaired adrenal response to stimulation, may account for the decreased production.

Dopamine-resistant hypotension and severe retinopathy of prematurity

OBJECTIVE

To examine the relationship between the cause or severity of hypotension and the development of severe ROP (sROP) (≥stage 3 or stage 2 with plus disease in zone I or II).

STUDY DESIGN

Infants (<28 weeks' gestation, n = 242) were observed for hypotension and treated with a standardized hypotension-treatment protocol. Hypotension was classified as resulting from one of the following causes: (1) culture-positive infection and/or necrotizing enterocolitis; (2) patent ductus arteriosus ligation; or (3) "idiopathic" (no cause identified other than prematurity), and as being either dopamine responsive or dopamine resistant. Cortisol levels were measured for infants with dopamine-resistant hypotension. Eye examinations were performed until the retinopathy of prematurity resolved or the vasculature matured. Multivariable logistic regression analysis was performed to determine the relationship between the cause/severity of hypotension and sROP.

RESULTS

Overall, 66% of infants developed hypotension (41% were dopamine responsive and 25% were dopamine resistant). sROP developed in 19% of infants. "Idiopathic" dopamine-resistant hypotension was the only cause significantly related to sROP. Of the infants with dopamine-resistant hypotension, 66% had low serum cortisol (≤10 μg/dL). Low cortisol, in the presence of dopamine-resistant hypotension, was significantly associated with sROP and accounted for the relationship between "idiopathic" hypotension and sROP. When low cortisol was included in statistical models, other known risk factors, such as immature gestation, were no longer significantly related to sROP.

CONCLUSION

Low cortisol, in the presence of dopamine-resistant hypotension, has the greatest magnitude of association with sROP.

Effect of hydrocortisone therapy on severe leaky lung syndrome in ventilated preterm infants

BACKGROUND

The aim of this study was (i) to determine the incidence and risk factors of severe leaky lung syndrome (sLLS), persistent pulmonary edema characterized by massive tracheal secretions and resistance to surfactant therapy, in extremely low gestational age newborns requiring ventilatory support; and (ii) to evaluate the effects of hydrocortisone (HC) therapy for sLLS on tracheal aspirate fluid (TAF) volume and β2-microglobulin levels in TAF.

METHODS

Infants born at <28 weeks gestation requiring ventilation beyond day of life (DOL) 7 were included. Daily TAF volume changes were assessed using a TAF scoring system. Levels of TAF β2-microglobulin, an indicator of capillary leakage, were measured at DOL0, 7, before, and 4 days after starting HC therapy (started at 4 mg/kg/day; tapered for 1-3 weeks).

RESULTS

Of the 54 infants enrolled, 24 (44%) were diagnosed with sLLS. Lower gestational age, lower birthweight, and higher TAF β2-microglobulin levels at DOL7 were independent risk factors for sLLS. Seventeen infants with sLLS received HC therapy starting at DOL17 (median), with subsequent decreases in TAF volume and β2-microglobulin levels.

CONCLUSIONS

The incidence of sLLS, as defined in this study, was 44% in extremely low gestational age newborns requiring ventilator support beyond a week. HC therapy effectively reduced TAF volume and β2-microglobulin levels, suggesting suppression of increased permeability of pulmonary capillaries in infants with sLLS.

Hydrocortisone and long-term outcomes in very-low-birthweight infants

BACKGROUND

The long-term effects of hydrocortisone (HDC) used for very-low-birthweight (VLBW) infants with chronic lung disease (CLD) are not fully understood. The aim of this study was to examine the short-term clinical effects and long-term impact of a physiological replacement dose of HDC on acute deterioration of CLD in VLBW infants.

METHODS

This prospective case-control study included 110 of the 174 VLBW infants admitted to our facility between 2003 and 2006 who were followed up to a corrected age of 18 months. Infant deaths and infants with congenital deformities were excluded from the study. The infants were classified into the following three groups: infants with CLD and treated with HDC (1-2 mg/kg/dose) due to progressive deterioration in oxygenation (CLD treatment group; n = 24); infants with CLD but not treated with HDC (CLD untreated group; n = 40); and infants without CLD (non-CLD group; n = 46).

RESULTS

The fraction of inspired oxygen (F(I) O(2) ) in the CLD treatment group improved significantly after treatment (P < 0.01). There were no significant differences among the three groups in terms of growth and neurodevelopmental quotient at the corrected age of 18 months following adjustment for birthweight, sex, and presence of light-for-date infants. There were also no significant intergroup differences in all three areas of developmental quotient.

CONCLUSIONS

Physiological doses of HDC replacement are effective in treating acute deterioration in oxygenation in VLBW infants with CLD. Furthermore, this treatment modality did not adversely affect the growth and development of infants at the corrected age of 18 months.

Evidence-based neonatal pharmacotherapy: postnatal corticosteroids

Corticosteroids are used in the neonatal intensive care unit primarily to treat two conditions: bronchopulmonary dysplasia (BPD) and hypotension (cardiovascular insufficiency). Historically, high-dose dexamethasone was used for BPD, but its use was later associated with adverse neurodevelopmental outcomes and decreased substantially. Data from randomized controlled trials regarding efficacy and safety of lower-dose dexamethasone therapy are insufficient to recommend its use. Hydrocortisone may be an alternative to dexamethasone, but again data are insufficient to support use. Hydrocortisone therapy is increasingly used to treat hypotension in critically ill newborns; however, the outcomes of this therapy must be evaluated in randomized trials.

Regulation of corticoid and serotonin receptor brain system following early life exposure of glucocorticoids: long term implications for the neurobiology of mood

Potent glucocorticoids (GC) administered early in life have improved premature infant survival dramatically. However, these agents may increase the risk for physical, neurological and behavior alterations. Anxiety, depression and attention difficulties are commonly described in adolescent and young adult survivors of prematurity. In the present study we administered vehicle, dexamethasone, or hydrocortisone to Sprague-Dawley rat pups on postnatal days 5 and 6, mimicking a short term clinical protocol commonly used in human infants. Two systems that are implicated in the regulation of stress and behavior were assessed: the limbic-hypothalamic-pituitary-adrenal axis [LHPA; glucocorticoid and mineralocorticoid receptors within] and the Serotonin (5-HT) system. We found that as adults, male Sprague-Dawley pups treated with GC showed agent specific altered growth, anxiety-related behavior, changes in corticoid response to novelty and gene expression changes within LHPA and 5-HT-related circuitry. The data suggest that prolonged GC-receptor stimulation during the early neonatal period can contribute to the development of individual differences in stress response and anxiety-related behavior later in life.

Postnatal corticosteroids for prevention and treatment of chronic lung disease in the preterm newborn

Despite significant progress in the treatment of preterm neonates, bronchopulmonary dysplasia (BPD) continues to be a major cause of neonatal morbidity. Affected infants suffered from long-term pulmonary and nonpulmonary sequel. The pulmonary sequels include reactive airway disease and asthma during childhood and adolescence. Nonpulmonary sequels include poor coordination and muscle tone, difficulty in walking, vision and hearing problems, delayed cognitive development, and poor academic achievement. As inflammation seems to be a primary mediator of injury in pathogenesis of BPD, role of steroids as antiinflammatory agent has been extensively studied and proven to be efficacious in management. However, evidence is insufficient to make a recommendation regarding other glucocorticoid doses and preparations. Numerous studies have been performed to investigate the effects of steroid. The purpose of this paper is to evaluate these studies in order to elucidate the beneficial and harmful effects of steroid on the prevention and treatment of BPD.

A preliminary study of cortisol reactivity and behavior problems in young children born premature

The purpose of the present study was to examine the relation between cortisol reactivity and comorbid internalizing and externalizing behavior problems among children born premature. Children between the ages of 18 and 60 months who were born <37 weeks gestation and presented with clinically significant externalizing behavior problems were included. Children were categorized based on those who mounted a cortisol response to a stressor and those who did not mount a cortisol response. Children demonstrating the cortisol response were reported to have more problems with attention, emotional reactivity, anxiety, and depression based on maternal report and displayed higher rates of negative verbalizations during a mother-child interaction than children without a cortisol response. These results extend the findings of the relation between cortisol reactivity and comorbid internalizing and externalizing behavior problems to a sample of children born premature.

A prospective longitudinal study to estimate the "adjusted cortisol percentile" in preterm infants

The normal range of serum cortisol concentrations and the appropriate levels of circulating cortisol in different clinical situations in preterm infants are not well defined. This study aimed to evaluate the impact of perinatal factors on circulating cortisol levels in preterm infants and to create a quantitative model that could estimate the "adjusted cortisol percentile." Serial serum cortisol concentrations were measured in 209 infants ≤ 32 wk gestation on d 1, 4, 7, 14, and 21 of life. Seven perinatal factors or conditions that could affect circulating cortisol level were identified. Serum cortisol levels were higher on d 4 (p = 0.007) and d 7 (p = 0.007) but lower on d 21 (p = 0.001) compared with d 1. Serum cortisol was also higher in infants on nasal continuous positive airway pressure (p = 0.003); requiring a second vasopressor (p < 0.001); with intraventricular hemorrhage (≥ grade 3; p < 0.001); with histologic chorioamnionitis (p = 0.007); with severe lung disease (p = 0.046); and with decreasing GA (p < 0.001). A mathematical equation was proposed based on factors derived in this preliminary study for estimating the adjusted cortisol percentile. Frontline neonatologists could now access the equation on our Web site (http://www.sta.cuhk.edu.hk/pswong/ACortP.html) to calculate the adjusted cortisol percentile, which could potentially improve the interpretation of circulating cortisol in different clinical situations.

Bronchopulmonary Dysplasia: Development and Progression in the Neonatal Intensive Care Unit

Advances in neonatology have led to increased survival at younger gestational ages. These advances have included the ability to provide and titrate oxygen, improved modalities of assisted ventilation, improved nutritional and environmental support, and surfactant therapy. As a result of increasing survival of these immature infants, bronchopulmonary dysplasia (BPD) has become a consistent outcome despite improvements in technology. Varying definitions of BPD have emerged in an effort to best identify infants at risk for long-term adverse outcome and those who might benefit most from preventive therapies. Underlying abnormal pulmonary development of extremely preterm infants in the face of exposure to oxygen, assisted ventilation and inflammation make this a complex, multifactorial disease. Recent focus has been directed at preventing and treating inflammation. Efforts to minimize the inflammatory process include avoiding hyperoxia, minimizing injury from assisted ventilation, and preventing and treating postnatal infections. Additional therapies to modulate inflammation, such as steroid therapy or inhaled nitric oxide, need further investigation of both short- and long-term outcomes before routine use can be recommended.

Clinical characterization and long-term prognosis of neurological development in preterm infants with late-onset circulatory collapse

OBJECTIVE

To characterize the risk factors for late-onset circulatory collapse (LCC) in preterm infants responsive to corticosteroid therapy and evaluate the long-term neurological prognosis.

STUDY DESIGN

A retrospective case-control study for preterm infants (≤32 weeks' gestation) admitted to our neonatal intensive care unit from 1994 through 2002.

RESULT

Sixty-five infants (11%) were diagnosed with LCC. Infants with a shorter gestation and lower birth weight had a higher incidence of LCC. LCC infants had a significantly lower 1-min Apgar score, significantly higher incidence of severe intraventricular hemorrhage, chronic lung disease, and postnatal periventricular leukomalacia, and significantly longer duration of ventilation use, oxygen use, and hospital stay. Somatic growth at 36 weeks' postmenstrual age was poorer in infants with LCC than without LCC (controls). LCC infants were significantly more likely than controls to have cerebral palsy at 3 years.

CONCLUSION

LCC is associated with poor neurodevelopmental outcomes. Prevention of LCC can lead to improved neurological prognoses.

Policy statement--postnatal corticosteroids to prevent or treat bronchopulmonary dysplasia

The purpose of this revised statement is to review current information on the use of postnatal glucocorticoids to prevent or treat bronchopulmonary dysplasia in the preterm infant and to make updated recommendations regarding their use. High-dose dexamethasone (0.5 mg/kg per day) does not seem to confer additional therapeutic benefit over lower doses and is not recommended. Evidence is insufficient to make a recommendation regarding other glucocorticoid doses and preparations. The clinician must use clinical judgment when attempting to balance the potential adverse effects of glucocorticoid treatment with those of bronchopulmonary dysplasia.

Serum cortisol values, superior vena cava flow and illness severity scores in very low birth weight infants

OBJECTIVE

Recent evidence suggests that high cortisol concentrations are associated with increased morbidity and mortality in very low birth weight (VLBW) infants. Neonatal illness severity and mortality risk scores are reliable in predicting morbidity and mortality. The objectives were (i) to assess the correlation between serum cortisol levels and clinical assessment of multi-organ dysfunction/illness severity scores (CRIB II, SNAPPE-II and neonatal multiple organ dysfunction score (NEOMOD)) in first 24 h in VLBW infants and (ii) to assess the relationship between surrogates of end organ blood flow and serum cortisol levels.

STUDY DESIGN

A prospective observational cohort study. Neonates with birth weight <1500 g were eligible for enrollment. Echocardiography evaluation of superior vena cava (SVC) flow was carried out in the first 24 h life. Cortisol levels were measured simultaneously and appropriate clinical scores were calculated.

RESULT

A total of 54 VLBW neonates were enrolled following parental consent. Two patients were excluded because of congenital malformations. In 14 babies the cortisol value was not simultaneously obtained. The mean birth weight was 1.08 kg, mean gestational age was 27.8 weeks. There was a significant correlation between cortisol and NEOMOD score (P=0.006). There was no correlation between cortisol and CRIB II score (P=0.34), SVC flow (P=0.49) and mean arterial blood pressure respectively (P=0.35).

CONCLUSION

There was no correlation between SVC flow and cortisol values or between cortisol and mean blood pressure values. There was a significant correlation between cortisol levels and neonatal organ dysfunction score evaluated suggesting that stressed VLBW infants do mount a cortisol response.

Thyroid function in term and late preterm infants with respiratory distress in relation to severity of illness

BACKGROUND

Transient hypothyroxinemia is common in extremely premature infants, but has not been extensively investigated in ill term and late preterm infants. We hypothesized that free thyroxine (T(4)) levels in term and late preterm infants with respiratory distress would be inversely related to severity of illness

METHODS

Eligible infants included those had > or =35 weeks of gestation requiring mechanical ventilation or nasal continuous positive airway pressure. Thyroid function (thyroid-stimulating hormone, T(4), free T(4) [fT(4)], and free triiodothyronine) and cortisol levels were collected at four specified intervals (birth, day 2, day 3, and day 5 of life). Illness severity was measured using score for neonatal acute physiology (SNAP). Infants with an SNAP > or =10 were considered to have severe illness. Statistical analysis included repeated measures analysis of variance.

RESULTS

A total of 20 patients were enrolled in the study. The mean gestational age of study infants was 37.0 +/- 1.7 weeks. Infant with SNAP > or =10 had a diminished thyroid-stimulating hormone at birth. There was an inverse correlation between SNAP at birth and fT(4.) There was also an inverse correlation between lowest measured fT(4) and highest mean airway pressure, oxygenation index, and A-a gradient. Infants who received inhaled nitric oxide had diminished fT(4) levels compared to infants who did not receive this therapy. There were no differences in cortisol in those infants with and without SNAP > or =10 during the study period.

CONCLUSIONS

In our study sample, there was an association between severity of illness and fT(4) levels at birth, and infants requiring inhaled nitric oxide showed decreased fT(4) over the study time. Further research is warranted to determine whether T(4) supplementation would be beneficial in term and late preterm infants with respiratory distress.

EFFECT OF HYPEROXIA ON INTERLEUKIN-8 EXPRESSION IN PREMATURE VERSUS TERM RABBIT LUNG EXPLANTS

To examine whether prematurity significantly changes the lung inflammatory response to oxygen, rabbit lung explant cultures were exposed to 95% or 5% oxygen for 24 hours. Interleukin (IL)-8 protein concentrations from homogenates of the premature lung rose significantly after hyperoxia (6.8 +/- 1.8 in 5% O2 to 45.7 +/- 21.3 pg/microg protein in 95% O2) but not in the term lung (15.9 +/- 6.7 to 20.4 +/- 4.3 pg/microg protein). There was no change in IL-8 mRNA after hyperoxia in either age group. Preterm lungs demonstrated higher IL-8 levels by fluorescence-activated cell sorting (FACs) analysis and immunohistochemistry. This model may help determine why premature lungs are more susceptible to oxygen-induced disease.

Use of steroid profiling by UPLC-MS/MS as a second tier test in newborn screening for congenital adrenal hyperplasia: the Utah experience

Newborn screening allows the diagnosis of congenital adrenal hyperplasia (CAH) before symptoms appear, preventing the severe and potentially life-threatening crisis associated with this disease in infancy. Traditional screening by enzyme immunoassay results in a large number of false positives. To reduce the number of unnecessary tests, anxiety to families and physicians, and the burden to the newborn screening follow-up program, we implemented a second-tier test for CAH using steroid profiling by an ultra-performance liquid chromatography-tandem mass spectrometry. We measured three steroids: 17-hydroxyprogesterone, androstenedione, and cortisol and correlated them with the age of infant at the time of sample collection and birth weight. Both age at collection and birth weight affected the levels of adrenal steroids, but the use of appropriate cut offs and analyte ratios allowed the identification of infants with CAH. This approach was effective in identifying infants with CAH, with both salt-wasting and simple virilizing forms, while reducing the false-positive rate from 2.6 to 0.09%.

Relative adrenal insufficiency in the preterm and term infant

Cortisol release in the face of illness or stress is vital for survival. Relative adrenal insufficiency occurs when a patient's cortisol response is inadequate for the degree of illness or stress. Numerous studies have documented the existence of relative adrenal insufficiency in critically ill adults, and its association with increased morbidity and mortality. There is increasing evidence that relative adrenal insufficiency may be an etiology for hemodynamic instability and hypotension in the critically ill newborn, but compared with the adult population, there is still a paucity of data in this population. Randomized controlled trials are needed to evaluate the efficacy and safety of glucocorticoids for the treatment of cardiovascular insufficiency due to relative adrenal insufficiency in ill preterm and term newborn infants.